Microtome with means for collecting sections of the specimen on a tape

ABSTRACT

A Microtome for section-cutting in particular of biological specimens and especially fresh-frozen specimens embedded in an ice block, comprising a knife and a specimen holder reciprocatingly moveable relative each other in a cutting stroke and opposite return stroke so that during the cutting stroke the knife passes above the specimen holder and can cut a section from the upper surface of a specimen block supported by the specimen holder. A tape extends from a wind-off supply roll to a wind-on collecting roll above the knife and the specimen holder preferably in a direction parallel to the direction of the manual movement between the knife and the specimen holder. During the cutting stroke the tape is pressed against the upper surface of the specimen block on the specimen holder immediately in front of the knife. The tape is preferably provided with an adhesive coating on its lower side and the section cut from the specimen block adheres to the lower side of the tape pressed against the surface of the specimen block during the cutting of the section. In the interval between two successive cutting strokes the tape is fed from the wind-off supply roll to the wind-on collecting roll by a length of tape substantially equal to the length of the cutting stroke, whereby the sections cut from the specimen block are obtained mounted in an orderly sequence upon the tape wound onto the collecting roll. Between successive cutting strokes the specimen holder is raised towards the knife by a predetermined number of incremental steps, whereby the thickness of the next section to be cut from the specimen block is determined. The operation of the microtome is automatically controlled by a control unit according to a preset program, which may be varied so that different sections of different thicknesses are cut from the specimen block and so that only predetermined sections of the total number of sections cut from the specimen block are collected on the tape, whereas the remaining sections are discarded.

Sept. 12, 1972 s. s. F. ULLBERG 3,690,933

v HICROTOME WITH MEANS FOR COLLECTING SECTIONS OF 3 Sheets-Sheet 1 THE SPECIMEN ON A TAPE Filed ow. 1a. 1969 b 12, 1972 s. s. F. ULLBERG 3,690,988

MEANS FOR COLLECTING SECTIONS OF MICROTOME WITH THE SPECIMEN ON A TAPE 3 Sheets-Sheet 2 Filed Dec. 16, 1969 s. s. F. ULLBERG 3,690,988 MEANS FOfi COLLECTING SECTIONS OF Sept. 12, 1972 MICROTOME WITH THE SPECIMEN ON A TAPE Filed Dec. 16. 1969 3 Sheets-Sheet 5 A mmuEmao E32 umetuu 23 umstou 3,690,988 MICROTOME WITH MEANS FOR COLLECTING SECTIONS OF THE SPECIMEN ON A TAPE Sven Gustav Folke Ullberg, Danderyd, Sweden, assignor to Incentive Research & Development AB, Bromma,

Sweden Filed Dec. 16, 1969, Ser. No. 885,535 Int. Cl. B2611 4/46 US. Cl. 156-353 9 Claims ABSTRACT OF THE DISCLOSURE A microtome for section-cutting in particular of biological specimens and especially fresh-frozen specimens embedded in an ice block, comprising a knife and a specimen holder reciprocatingly movable relative each other in a cutting stroke and opposite return stroke so that during the cutting stroke the knife passes above the specimen holder and can cut a section from the upper surface of a specimen block supported by the specimen holder. A tape extends from a wind-off supply roll to a wind-on collecting roll above the knife and the specimen holder preferably in a direction parallel to the direction of the mutual movement between the knife and the specimen holder. During the cutting stroke the tape is pressed against the upper surface of the specimen block on the specimen holder immediately in front of the knife. The tape is preferably provided with an adhesive coating on its lower side and the section cut from the specimen block adheres to the lower side of the tape pressed against the surface of the specimen block during the cutting of the section. In the interval between two successive cutting strokes the tape is fed from the wind-otf supply roll to the wind-on collecting roll by a length of tape substantially equal to the length of the cutting stroke, whereby the sections cut from the specimen block are obtained mounted in an orderly sequence upon the tape wound onto the collecting roll. Between successive cutting strokes the specimen holder is raised towards the knife by a predetermined number of incremental steps, whereby the thickness of the next section to be cut from the specimen block is determined. The operation of the microtome is automatically controlled by a control unit according to a preset program, which may be varied so that dilferent sections of different thickness are cut from the specimen block and so that only predetermined sections of the total number of sections cut from the specimen block are collected on the tape, whereas the remaining sections are discarded.

The invention is related to microtomes, in particular for section-cutting of biological specimens, which are of the well-known general type comprising a support member or stand and a carriage member linearly movable relative to the support member, a knife being mounted on one of said two mutually movable members, generally on the stationary support member, and a specimen holder being mounted on the other member, i.e. generall on the carriage member, in such a way that during the cutting stroke of the carriage member the knife passes above the specimen holder and can cut a section from the upper surface of a specimen supported by the specimen holder.

Section-cutting of biological specimens for producing necessary sections for subsequent studies and tests, as for instance light microscopy, autoradiography, histochemistry, fluorescence microscopy etc., has hitherto been a very time-consuming work requiring very skilled personnel with long experience. One reason for this is that when using prior types of microtomes it is very difficult to handle the generally very thin sections in such a way that they remain undamaged. Further, when cutting larger specimens it is difiicult among the very large number of sections being United States Patent 6 Patented Sept. 12, 1972 produced to select exactly those sections that may be of interest for subsequent studies and tests. In this case it is also extremely difficult to keep a check on which portions of the original specimen that the selected sections come from. For systematic studies on larger specimens it is often desired that a comparatively large number of sections from different depths" in the specimen can be studied. When section-cutting with prior types of microtomes, however, it is an extremely time-consuming and very difficult task to collect and store a large number of sections and to keep track of the mutual order of these sections in the specimen being cut. The difficulties become still more severe when cutting sections having a large area and when section-cutting non-homogeneous specimens, as for in-- stance section-cutting entire animals, as with prior types of microtomes large-area sections are easily deformed and distorted during the cutting process and also easily fall into pieces when being handled after the cutting process.

The object of the present invention is therefore to provide an improved microtome of the general type mentioned in the foregoing, in which the section-cutting of a specimen can be carried out substantially automatically while collecting, if desired, a very large number of sections from different predetermined depths in the specimen and in which it is also possible to cut sections having a very large area as well as to cut non-homogeneous specimens, as for instance entire animals, without the sections being distorted or deformed by the knife during the cutting process or falling into pieces after the cutting process.

The microtome according to the invention is characterized in that it comprises a wind-off supply roll and a windon collecting roll for a tape mounted on the member, the support member or the carriage member, carrying the specimen holder on opposite sides of the specimen holder so that the tape extends between the rolls above the specimen holder, vertically movable means mounted on the member carrying the knife for pressing the tape against the upper surface of a specimen held in the specimen holder in front of the edge of the knife, tape-feeding means for feeding the tape from the supply roll to the collecting roll intermittently in steps each equal to a length of tape substantially equal to the length of the cutting stroke of the carriage member, and control means for controlling the driving means for the carriage member, the means for pressing the tape against the specimen and the tape feeding means in such a manner that the tape is pressed against the upper surface of the specimen during the cutting stroke of the carriage member and moved one feeding step during the return stroke of the carriage member.

The tape is preferably provided with an adhesive layer on its lower surface, that is on the surface of the tape facing the specimen.

Further, the microtome comprises preferably means controlled by the control means for raising the specimen holder in a stepwise manner in the intervals between successive cutting strokes of the carriage member.

As in a microtome according to the invention the tape, which preferably is provided with an adhesive layer on its lower surface and preferably consists of a transparent, colourless plastic film, is pressed against the upper surface of the specimen in front of the edge of the knife during the cutting process, the section being cut is backed and supported by the tape, wherefore it will not be deformed or distorted (compressed) by the knife during the cutting process. Further, when separated from the specimen the section will adhere to the adhesive tape and thereby be prevented from falling into pieces. Using a microtome according to the invention, it is therefore possible to produce also very large and thin sections, for instance from entire animals as for instance mice. Further, the various sections cut from the specimen are obtained mounted in an orderly sequence on the tape, whereby it becomes possible to collect and store also a very large number of sections from a specimen and keep check on from which different depths in the specimen the different sections are derived. The control unit of the microtome can easily and by use of conventional technique be designed to control the section-cutting of an entire specimen automatically after a predetermined program, which the control unit is designed to perform or preferably which is variable and has been set into the control unit before the section-cutting operation. By programming the control unit to control the means for the stepwise raising of the specimen holder to raise the specimen holder a different number of steps between different successive cutting strokes of the carriage member, sections with different thicknesses can be cut from the specimen. Further, the control unit may be programmed to control the means pressing the tape against the specimen in such a way that the tape is pressed against the upper side of the specimen only during certain predetermined cutting strokes of the carriage member, whereas during other cutting strokes of the carriage member the tape is not pressed against the specimen. In this way only certain sections as determined by the program will be collected on the tape, whereas the remaining sections, i.e. those out when the band is not pressed against the specimen, are discarded and may be removed from the specimen by means of a suitable suction device. In this way large specimens may be examined systematically, only a reasonable number of predetermined sections being collected and stored and the positions of these collected sections in the original specimen being well-known from the predetermined program for the section-cutting operation.

The processing and examination of the sections after the cutting thereof, as for instance freeze-drying, dyeing, autoradiography, mounting between slides and coverglasses, microscope studies, photography etc., can be carried out with the sections mounted on the tape. In this way the handling of the sections is facilitated very considerably and it is also prevented that the sections fall into pieces or are damaged in some other way. Certain types of tape are capable of keeping the sections in place on the tape also when being submerged in alcohols or dyeing liquids. The tape itself will not absorb dyes in any substantial extent. The tape with an adhering section can also be mounted between a slide and a cover-glass by the use of suitable mounting agents (for instance Canada turpentine or Euparat) without any disturbing light refraction phenomena being produced.

The microtome according to the invention can be used for the section-cutting of specimens treated in various ways, as for instance set with chemical agents, freeze-dried and embedded in paraffin, fresh-frozen specimens embedded in ice blocks etc. As the microtome according to the invention makes an automatic section-cutting process possible, the microtome can be enclosed in a heat insulated casing or cover provided with a refrigerator unit for refrigeration of the interior of the casing or cover, so that the section-cutting of fresh-frozen specimens at temperatures below the freezing point can be carried out without any inconvenience to the operator.

In the following the invention will be further described with reference to the accompanying drawing, which shows by way of example an embodiment of a microtome according to the invention.

In the drawing:

FIG. 1 is a schematical side view, partially in section, of a microtome according to the invention;

FIG. 2 is a top view of the same microtome; and

FIG. 3 is a diagram illustrating by way of example some operating cycles for the microtome illustrated in FIGS. 1 and 2.

The microtome according to the invention schematically shown by way of example in FIGS. 1 and 2 is arranged in a heat insulated box or cabinet 1, preferably prvided with a cover 2. A conventional refrigerator unit 3,

illustrated only schematically in the drawing, is provided for refrigeration of the interior of the box, whereby the microtome can be used for section-cutting of fresh-frozen specimens at temperatures below zero.

The microtome as such comprises in conventional way a stationary stand or supporting member 4 and a carriage 5 which is supported by the stand 4 and reciprocatingly movable relative thereto along a straight guide path. A stationary knife 7 is mounted at the upper ends of two posts 6 supported by the stand 4 so that the edge of the knife extends horizontally in a direction perpendicular to the direction of movement of the carriage 5. If desired, the knife may also be adjusted in a position oblique to the direction of movement of the carriage. The carriage 5 supports a specimen holder 8 on which the specimen to be cut can be held. In the illustrated embodiment it is assumed that the specimen is a fresh-frozen specimen embedded in an ice block 9. The specimen holder 8 is mounted at the upper end of a screw 10 extending through a nut 11, which is rotatably mounted in the carriage 5, whereby the specimen holder 8 can be raised towards the knife 7 by rotation of the nut 11. The nut 11 is provided with a gear rim in engagement with a gear wheel 12 connected to an electric stepping motor 13, by means of which the specimen holder 8 can be raised in accurately predetermined increments, for instance in increments of the order of about 1 am. Of course, also other devices than an electric stepping motor can be used for an accurate stepwise rotation of the nut 11. The carriage 5 with the specimen holder 8 is in the illustrated embodiment driven by a pneumatic cylinder 14, which is mounted on the stand 4 with its piston rod 15 connected to the carriage 5, whereby this can be given a reciprocating motion relative to the stand 4 comprising a cutting stroke in direction towards the edge of the knife 7 and an opposite return stroke. In the drawing the carriage 5 is shown in its end position constituting the starting position for the cutting stroke. During the reciprocating motion of the carriage 5 the specimen holder 8 with the specimen block 9 supported thereon passes underneath the knife 7, whereby the knife during the cutting stroke cuts a section from the upper side of the specimen block 9, the thickness of the section being determined by the number of increments by which the specimen holder 8 has been raised by means of the stepping motor 13 after the immediately preceding cutting stroke.

Instead of a pneumatic cylinder 14 it is of course also possible to use a hydraulic cylinder, an electric motor or any similar motive element for imparting the reciprocating motion to the carriage 5.

Further, the carriage 5 carries a wind-off supply roll 16 for a tape 18 having an adhesive layer on its one side; in the illustrated example on the side facing inwards in the roll. The tape consists preferably of a transparent, noncoloured plastic film of a more or less conventional type. The tape roll 16 is mounted rotatably in two pillars 17 supported by the carriage 5. The tape '18 can be woundoff from the supply roll 16 and wound onto a collecting roll 19 which is mounted rotatably in two pillars 20 at the opposite end of the carriage 5. The supply roll 16 and a guide roll 21 for the tape 18 are positioned on the carriage 5 in such a way that the tape 18 extends between the rolls above the knife 7 and the specimen holder 8 substantially parallel to the direction of movement of the carriage 5. Preferably the tape 18 has a breadth at least equal to the breadth of the specimen block 9 supported on the specimen holder. The side of the tape provided with the adhesive layer is facing the upper surface of the specimen block 9.

The wind-on collecting roll 19 for the tape 18 is provided with a one-way rotation catch 22, illustrated only schematically in the drawing, permitting rotation of the collecting roll 19 only in the wind-on direction indicated by an arrow 23 in FIG. 1. The collecting roll 19 is ro tated in its wind-on direction in a manner to be described in further detail in the following by means of a rope pulley 24, which is coupled to the shaft of the roll 19 and over which a rope 25 is running. One end of the rope 25 is attached to a weight 26, whereas the opposite end of the rope is attached to a point 27 which is stationary relative to the stand 4.

Two posts or pillars 28 mounted on the stand 4 support a vertically movable brush 29 having a breadth at least equal to the breadth of the tape 18. The brush 29 is positioned at a short distance in front of the edge of the knife 7 and can be lowered and raised by means of a pneumatic cylinder, hydraulic cylinder, solenoid or a similar device 30. In its lowered position the brush 29 presses the tape 18 against the upper surface of the specimen block 9 supported on the specimen holder 8 immediately in front of the edge of the knife 7, provided the carriage is in such a position that the specimen holder 8 is located underneath the brush 29.

A post 31 mounted on the stand 4 supports two rollers 32 and 33 positioned on opposite sides of the tape 18. At least one of these rollers is rotatable only in the one direction. In FIG. 1 the two rollers 32 and 33 are illustrated in their normal separated positions, for which the tape 18 can move freely between the rollers 32 and 33. By means of a pneumatic cylinder, hydraulic cylinder, solenoid or a similar device 34, however, the two rollers can be moved towards each other so that the tape 18 is pinched between them.

Further, an air suction device 35, as for instance a fan or similar (shown only schematically in the drawing) is connected through a tube 36 to a suction nozzle 37 mounted on the carriage 5 so as to have its opening located immediately adjacent the upper side of the specimen block 9 on the specimen holder 8.

The driving means 14 for the reciprocating movement of the carriage 5, the operating means 30 for raising and lowering the brush 29, the operating means 34 for the pinch rollers 32, 33 and the suction fan 35 are controlled from a control unit 38, which is not shown in detail as it can consist of conventional components and be designed according to well-known principles of automatic control. The control unit 38 is designed to control the abovementioned operating means in the microtome and thus the cutting operation of the microtome according to a predetermined, preferably variable program. The connections between the control unit 38 and the different operating means in the microtome are for the sake of simplicity not shown, as they can consist of electric conductors, hydraulic conduits or pneumatic conduits dependent upon the type of operating means used in the microtome. The control unit 38 receives information about the state of operation of the microtome from a number of microswitches on the microtome.

Thus two switches 39 and 40 are provided, which are mounted on the side of the stand 4 and are actuated by an actuating cam 41 mounted on the carriage 5 so that these two switches indicate the two end positions of the reciprocating movement of the carriage 5. Further, two switches 42, 43 are provided, which are mounted on the stand 4 in the same way as the switches 39 and 40 and which also are actuated by the cam 41 on the carriage 5. These switches 42 and 43 determine those positions of the carriage 5 in which the brush 29 is respectively lowered to press the tape 18 against the specimen block 9 and is raised again. A fifth switch 44 is mounted on the stand 4 so as to be actuated by an elongated cam 45 mounted on the carriage 5. The function of this switch 44 is to determine the time interval during which the suction device 35 shall operate. The microtome may also be provided with additional switches, not illustrated in the drawing, for the control and the monitoring of the correct operation of the microtome. Thus, for instance, a switch may be provided for sensing the tape 18 and causing the control unit 38 to stop the operation of the microtome if the tape 18 should break. A switch may also be provided for sensing the upper end position for the specimen holder 6 8 so that the specimen holder cannot be raised to such a height that the knife 7 will cut into the specimen holder 8 itself. Means may also be provided for monitoring the stepwise raising of the specimen holder 8 by means of the screw 10.

FIG. 3 illustrates schematically three subsequent complete operation cycles 1, II and III for the microtome shown in FIGS. 1 and 2. As seen in the drawing, each operation cycle consists of three portions a, b and c. During the first portion a of the operation cycle I the carriage 5 with the specimen holder 8 performs a cutting stroke in that it is moved by means of the pneumatic cylinder 14 from its right-hand end position illustrated in FIGS. 1 and 2 towards the knife 7 to its left-hand end position determined by the switch 39. During this cutting stroke the knife 7 cuts a section from the upper surface of the specimen block 9 supported on the specimen holder 8. When the knife 7 has cut a small distance into the specimen block 9, the brush 29 is lowered by means of its operating means 30 so that the adhesive lower side of the tape 18 is pressed against the upper surface of the specimen block 9 immediately in front of the edge of the knife 7. The brush 29 is kept in this lowered position until a moment immediately before the knife 7 has passed completely through the specimen block 9. Thus, the brush 29 is raised somewhat before the section-cutting is cornpleted. As the tape 18 is pressed against the upper surface of the specimen block 9 immediately in front of the edge of the knife 7 during the major portion of the cutting operation, the section being cut from the specimen block is backed and supported by the tape 18 so that it cannot be disformed or distorted by the pressure from the knife edge. The section cut from the specimen block 9 is automatically lifted from the block 9 and adheres to the tape 18 through the adhesive layer thereon. In this way the section is prevented from falling into pieces.

During the cutting stroke the wind-on collecting roll 19 carried by the carriage 5 and the rope pulley 24 coupled to the roll 19 move to the left in FIGS. 1 and 2 relative to the rope 25, whereby the weight 26 attached to the free end of the rope is raised. The rope 25 strives to rotate the rope pulley 24 in the clockwise direction in FIG. 1. However, the rope pulley cannot rotate the collecting roll 19 in this direction, as this is prevented by the one-way rotation catch 22. Preferably the rope pulley 24 is coupled to the shaft of the collecting rod 19 through a friction coupling preventing the rope pulley 24 exerting an unacceptably large rotational torque upon the collecting roll 19. 1

When the carriage '5 has completed its cutting stroke and reached its left-hand end position determined by the switch 39, the portion b of the operation cycle starts. During this the carriage 5 is returned to the right in FIG. 1 or 2 by means of the pneumatic cylinder 14 to the starting position illustrated in FIGS. 1 and 2, in which the carriage 5 is stopped due to the actuation of the switch 40 from the cam 41. During this return stroke of the carriage 5 the two pinch rollers 32 and 33 are kept in their closed position by their operating means 34, whereby the tape 18 is clamped by the pinch rollers 32 and 33 which are stationary relative to the stand 4. As the supply roll 16 for the tape l18 is moving to the right in FIGS. 1 and 2 together with the carriage 5 during the return stroke thereof, the tape 18 will obviously be wound off from the supply roll 16 with a length of tape equal to the length of the stroke of the carriage 5. At the same time also the wind-on collecting roll 19 with the rope pulley 24 moves to the right in FIGS. 1 and 2 relative to the rope 25 so that the weight 26 is lowered again. The rope 25 rotates then the rope pulley 24 and thus also the collecting roll 19 in the wind-on direction indicated by the arrow 23, whereby the tape 18 is wound onto the collecting roll 19. The friction coupling between the collecting roll 19 and the rope pulley 24 prevents rotational torque exerted upon the collecting roll 19 becoming sufficiently large for causing rupture of the tape 18. Consequently, during the return stroke of the carriage the tape 18 and the specimen section adhering thereto is fed from the supply roll 16 to the collecting roll '19 with a length of tape equal to the length of the stroke of the carriage 5.

As illustrated in FIG. 3, the suction device 35 is operating during the last portion of the cutting stroke of the carriage and the first portion of the return stroke of the carriage, whereby chips, splinters and other small particles that some loose from the specimen block 9 during the cutting process, in particular from the material in which the specimen as such is embedded, are sucked away through the suction nozzle 37.

When the return stroke of the carriage 5 is completed, the two pinch rollers 32 and 33 are separated again by means of their operating means 34 so that the tape 18 is released.

During the last portion 0 of the operation cycle the stepping motor 13 is supplied from the control unit 38 with stepping pulses in a number determined by the preset program of the control unit 38, whereby the specimen holder 8 with the specimen block 9 is raised a corresponding number of equally large incremental steps. Consequently, the number of stepping pulses supplied to the stepping motor 13 during portion c of the operation cycle determines the thickness of the section that will be cut from the specimen during the next cutting cycle.

When an operation cycle of the type described above is completed, the control unit 38 starts automatically a new operation cycle, unless the desired section-cutting process of the specimen has been completed.

As a comparison between the different operation cycles 1, II and II in FIG. 3 shows, the program for the control unit 38 may be such that the stepping motor 13 is caused to raise the specimen holder 8 by different amounts, i.e. different numbers of increments, during different operation cycles, whereby sections of different thickness can be cut from the specimen.

As illustrated by the operation cycle III in FIG. 3, the program preset in the control unit 38 can also be such that during certain predetermined operation cycles the brush 29 is not lowered to press the tape 18 against the specimen block 9. Consequently, the section cut from the upper surface of the specimen block 9 during such an operation cycle will not be collected on the tape 18 but instead be sucked away through the suction nozzle 37. During such an operation cycle the pinch rollers 32 and 33 are not brought together during the return stroke of the carriage 5, wherefore no feed motion of the tape 18 is carried out. Of course, a feeding step for the tape 18 is superfluous during such an operation cycle, as no section has been collected on the tape. Consequently, the program for the control unit 38 can be such that only certain predetermined sections are collected and stored on the tape. In this way a large specimen can be examined systematically with a reasonable number of sections being collected from different predetermined depths in the specimen.

It is appreciated from the foregoing that the sections collected during a section-cutting process will be mounted in an orderly sequence on the tape 18 wound onto the collecting roll 19. After the completed section-cutting process the collecting roll 19 with the tape wound thereon and the collected sections adhering to the tape can be removed from the microtome for subsequent treatment and examination of the sections.

If the specimen is a freshfrozen specimen embedded in an ice block which has been section-cut at a temperature below zero, the collected section shall generally be freezedried at first. This can be done with the sections remaining on the tape 18 and is most simply carried out with the tape 18 still wound on the collecting roller 19 which has been removed from the microtome. In order to obtain an effective and rapid freeze-drying of the sections it is necessary, however, that the air can reach the sections on the wound tape. In order to facilitate this the microtome according to the invention may be provided with an additional wind-off supply roll 46 for a band 47. This supply roll 46 is mounted rotatably in the columns 20 supporting the collecting roll 19 in such a way that the band 47 via a guide roll 48 can be wound onto the collecting roll 19 together with the tape 18 supporting the collected sections. In this way the band 47 becomes inter- N6116d between the turns of the tape 18. The band 47 may preferably consist of a loose net or fabric, for instance of plastic, textile, glass fiber or similar material, so that it permits air circulation between the different turns of the tape 18 carrying the sections.

Various modifications are of course possible within the scope of the invention. Thus, for instance, the driving means for the wind-on collecting roll may be designed in several different ways as well as the driving means for the carriage 5 and the operating means for the brush 29 and the pinch rollers 32 and 33 respectively. The means for clamping the tape 18 during the return stroke of the carriage 5 can of course be designed in some other way than that illustrated in FIGS. 1 and 2. It is also appreciated that the knife 7 together with the brush 29 and the pinching means 32, 33 for the tape 18 could instead be mounted on the movable carriage 5 with the specimen holder 8 and the tape rolls mounted on the stationary stand, without this causing any changes in the principal operation of the microtome.

What is claimed is:

1. A microtome comprising a support member (4), a carriage member (5) reciprocatingly movable relative to the support member, driving means (14) for reciprocating the carriage member in a cutting stroke and an opposite return stroke, a knife (7) mounted on one of said two mutually movable members and a specimen holder (8) mounted on the other one of said two mutually movable members in such a way that during a cutting stroke of said carriage member said knife passes above said specimen holder and can cut a section from the upper surface of a specimen (9) held in said specimen holder, characterized by a wind-off supply roll (16) and a wind-on collecting roll (19) for a tape (18), said supply roll and collecting roll being rotatably mounted on the member (5) carrying said specimen holder (8) on opposite sides of the specimen holder so that said tapes extend between said rolls above said specimen holder, vertically movable means (29) mounted on the member (4) carrying said knife (7) for pressing said tape against the upper surface of a specimen held in said specimen holder in front of the edge of said knife, tape feeding means (32, 33, 43, 24, 25, 26) for feeding said tape from said supply roll to said collecting roll in a stepwise manner with a length of tape in each feeding step substantially equal to the length of the cutting stroke of the carriage member, and control means (38) for controlling the operation of said driving means (14) for said carriage member, of said means (29) for pressing said tape against the specimen and of said tape feeding means so that the tape is pressed against the specimen during the cutting stroke of the carriage member and is fed from said supply roll to said collecting roll during the return stroke of the carriage member.

2. A microtome as claimed in claim 1, wherein said tape (18) is provided with an adhesive layer on the side of the tape facing the specimen.

3. A microtome as claimed in claim 1, wherein the supply roll (16) and the collecting roll (19) are so positioned that the tape (18) extends between the said rolls substantially parallel to the direction of movement of the carriage member (5).

4. A microtome as claimed in claim 3, wherein said tape feeding means comprise means (32, 33) mounted on the member (4) carrying said knife (7 and controlled by said control means (38) for holding said tape locked during the return stroke of the carriage member and means (24, 25, 26) for exerting a rotational torque upon said collecting roll (19) in the wind-on direction (23) thereof at least during the return stroke of the carriage member.

5. A microtome as claimed in claim 1, wherein said means for pressing said tape (18) against the upper surface of the specimen (9) consist of a brush (29).

6. A microtome as claimed in claim 1, comprising means (13) responsive to said control means (39) for raising said specimen holder (8) in a stepwise fashion towards said knife (7) in the intervals between successive cutting strokes of the carriage member.

7. A microtome as claimed in claim 1, comprising suc-.

tion means including a suction nozzle (37) located adjacent said specimen holder.

8. A microtome as claimed in claim 1, comprising an 16 10 9. A microtome as claimed in claim 1 enclosed in a seat insulating casing (1) and comprising refrigerator means (3) for refrigerating the interior of said casing.

References Cited UNITED STATES PATENTS 3,077,306 2/1963 Hellstrom 83--915.5 2,248,744 7/1941 Cohen 156-353 3,552,247 1/1971 Pickett 83-915.5 3,389,038 6/1968 Robinson, Jr. 156552 3,322,037 5/ 1967 Cavagnero 83l00 3,236,133 2/1966 De Pas 83-915.5

BENJAMIN A. BORCHELT, Primary Examiner D. BENT, Assistant Examiner US. Cl. X.R.

Patent No, 5,69 ,98 Dated September 12, 1972 lnvent r( Seven Gustav Folke Ullberg It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the heading, in column 1, after line 7, insert Claims priority, application Sweden, Deceinber' 16, 1968,

Signed and sealed this 31st day of December 1974..

(SEAL) v Attest:

McCOY M. GIBSON JR. 0. MARSHALL DANN Attesting Officer Commissioner of Patents FORM PO-10 0 USCQMM-DC 60376-P69 U 5 GOVERNMENY PRINTXNG OFFICE a 9 93 o 

